Process for hydroformylation of olefins using Pt and iodine

ABSTRACT

Process for hydroformylation of olefins using Pt and iodine.

The present invention relates to a process for hydroformylation ofolefins using Pt and iodine.

C. Botteghi et al., Journal of Molecular Catalysis A: Chemical 200,(2003), 147-156 describes the use of Pt(Xantphos)Cl₂ forhydroformylation of 2-tosyloxystyrene.

The problem addressed by the present invention is that of providing anovel hydroformylation process. The process here is to afford anincreased yield compared to the process known from the prior art usingPt(Xantphos)Cl₂.

This object is achieved by a process according to Claim 1.

Process comprising the process steps of:

a) initially charging an olefin;

b) adding a compound of formula (I):

where R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸ are selected from: —H,—(C₁-C₁₂)-alkyl, —(C₆-C₂₀)-aryl; and, if R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸are —(C₆-C₂₀)-aryl, the aryl ring may have substituents selected from:—(C₁-C₁₂)-alkyl, —O—(C₁-C₁₂)-alkyl;

c) adding a Pt compound capable of forming a complex;

d) adding an iodine compound;

e) feeding in CO and H₂;

f) heating the reaction mixture from steps a) to e), to convert theolefin to an aldehyde.

In this process, process steps a) to e) can be effected in any desiredsequence. Typically, however, CO and H₂ are added after the co-reactantshave been initially charged in steps a) to d).

It is possible here for process steps c) and d) to be effected in onestep, by adding PtI₂. In a preferred variant of the process, the Ptcompound and the iodine compound are added in one step, by adding PtI₂.

The expression (C₁-C₁₀-alkyl encompasses straight-chain and branchedalkyl groups having 1 to 12 carbon atoms. These are preferably(C₁-C₈-alkyl groups, more preferably (C₁-C₆)-alkyl, most preferably(C₁-C₄)-alkyl.

Suitable (C₁-C10-alkyl groups are especially methyl, ethyl, propyl,isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-pentyl,2-methylbutyl, 3-methylbutyl, 1,2-dimethylpropyl, 1,1-dimethylpropyl,2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 2-hexyl, 2-methylpentyl,3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl,2,2-dimethylbutyl, 1,3-dimethylbutyl, 2,3-dimethylbutyl,3,3-dimethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl,1-ethylbutyl, 1-ethyl-2-methylpropyl, n-heptyl, 2-heptyl, 3-heptyl,2-ethylpentyl, 1-propylbutyl, n-octyl, 2-ethylhexyl, 2-propylheptyl,nonyl, decyl.

The expression (C₆-C₂₀-aryl encompasses mono- or polycyclic aromatichydrocarbyl radicals having 6 to 20 carbon atoms. These are preferably(C₆-C₁₄)-aryl, more preferably (C₆-C₁₀-aryl.

Suitable (C₆-C₂₀-aryl groups are especially phenyl, naphthyl, indenyl,fluorenyl, anthracenyl, phenanthrenyl, naphthacenyl, chrysenyl, pyrenyl,coronenyl. Preferred (C₆-C₂₀-aryl groups are phenyl, naphthyl andanthracenyl.

In one variant of the process, R², R³, R⁵, R⁶, R⁷, R⁸ are selected from:—(C₁-C10-alkyl, —(C₆-C₂₀-aryl.

In one variant of the process, R⁵, R⁶, R⁷, R⁸ are —(C₆-C₂₀-aryl.

In one variant of the process, R⁵, R⁶, R⁷, R⁸ are —Ph.

In one variant of the process, R² and R³ are —(C₁-C10-alkyl.

In one variant of the process, R² and R³ are —CH₃.

In one variant of the process, R¹ and R⁴ are —H.

In one variant of the process, the compound (I) has the structure (1):

In one variant of the process, the Pt compound is selected from:Pt(II)I₂, Pt(IV)I₄, diphenyl(1,5-COD)Pt(II), Pt(II)(acac)₂,Pt(0)(PPh₃)₄, Pt(0)(DVTS) solution (CAS: 68478-92-2),Pt(0)(ethylene)(PPh₃)₂, tris(benzylideneacetone)Pt(0), Pt(II)(OAC)₂solution, Pt(0)(t-Bu)₂, Pt(II)(COD)Me₂, Pt(II)(COD)I₂, Pt(IV)IMe₃,Pt(II)(hexafluoroacetylacetonate)₂.

In one variant of the process, the Pt compound is selected from:Pt(II)I₂, Pt(II)(acac)₂.

In one variant of the process, the iodine compound is selected from:alkali metal halide, alkaline earth metal halide, NH₄X, alkylammoniumhalide, dialkyl halide, trialkyl halide, tetraalkyl halide,cycloalkylammonium halide.

In one variant of the process, the iodine compound is selected from:Pt(II)I₂, LiI.

In one variant of the process, the iodine compound is added in an amountin the range of 0.1 to 10, measured in equivalents based on Pt.

In one variant of the process, this process comprises the additionalprocess step e′): e′) adding a solvent.

In one variant of the process, the solvent is selected from: THF, DCM,ACN, heptane, DMF, toluene, texanol, pentane, hexane, octane, isooctane,decane, dodecane, cyclohexane, benzene, xylene, Marlotherm, propylenecarbonate, MTBE, diglyme, triglyme, diethyl ether, dioxane, isopropanol,tert-butanol, isononanol, isobutanol, isopentanol, ethyl acetate.

In one variant of the process, the solvent is selected from: THF, DCM,ACN, heptane, DMF, toluene, texanol.

In one variant of the process, CO and H₂ are fed in at a pressure in arange from 1 MPa (10 bar) to 6 MPa (60 bar).

In one variant of the process, CO and H₂ are fed in at a pressure in arange from 1 MPa (20 bar) to 6 MPa (50 bar).

In one variant of the process, the reaction mixture is heated to atemperature in the range from 25° C. to 150° C.

In one variant of the process, the reaction mixture is heated to atemperature in the range from 30° C. to 130° C.

In one variant of the process, the olefin is selected from: ethene,propene, 1-butene, cis- and/or trans-2-butene, isobutene, 1,3-butadiene,1-pentene, cis- and/or trans-2-pentene, 2-methyl-1-butene,3-methyl-1-butene, 2-methyl-2-butene, hexene, tetramethylethylene,heptene, 1-octene, 2-octene, di-n-butene, or mixtures thereof.

The invention shall be elucidated in more detail hereinbelow withreference to working examples.

EXPERIMENTAL DESCRIPTION

A vial was charged with PtX₂ (X=halogen), ligand, and an oven-driedstirrer bar. The vial is then sealed with a septum (PTFE-coatedstyrene-butadiene rubber) and phenolic resin cap. The vial is evacuatedand refilled with argon three times. Toluene and olefin were added tothe vial using a syringe. The vial was placed in an alloy plate, whichwas transferred to an autoclave of the 4560 series from Parr Instrumentsunder an argon atmosphere. After purging the autoclave three times withCO/H₂, the synthesis gas pressure was increased to 40 bar at roomtemperature. The reaction was conducted at 120° C./80° C. for 20 h/18 h.On termination of the reaction, the autoclave was cooled to roomtemperature and cautiously decompressed. Yield and selectivity weredetermined by GC analysis.

Variation of the Metal

Reaction conditions:

20 mmol of 1-octene, 0.1 mol % of metal, 2.2 equivalents of Xantphos(1), solvent: toluene, p(CO/H₂): 40 bar, T: 80° C., t: 20 h.

Yields:

PtI₂: 99%

PdI₂: 0%

Variation of the Halogen (2-octene)

Reaction conditions:

20 mmol of 2-octene, 1.0 mol % of Pt, 1.1 equivalents of Xantphos (1),solvent: toluene, p(CO/H₂): 40 bar, T: 120° C., t: 20 h.

Yields:

PtI₂: 99%

PtCl₂: 16%

Variation of the Halogen (1-octene)

Reaction conditions:

10.0 mmol of 1-octene, 0.1 mol % of PtX₂, 2.2 equivalents of ligand,solvent: toluene, p(CO/H₂): 40 bar, T: 120° C., t: 20 h.

Yields:

Ligand Halogen Yield [%]

I/Cl 99/5

Variation of the Olefin

Reaction conditions:

1.0 mmol of olefin, 0.5 mol % of PtI₂, 2.2 equivalents of Xantphos (1),solvent: dichloromethane (DCM), p(CO/H₂): 40 bar, T: 80° C., t: 18 h.

Yields:

Aldehyde Yield [%]

99

99

99

99

The C—C bond in bold indicates the position of the former double bond,i.e. the double bond in the olefin.

Variation of the Ligand and of the Halogen

Reaction conditions:

1.0 mmol of 1-octene, 0.5 mol % of PtX₂, 2.0 equivalents of ligand,solvent: toluene, p(CO/H₂): 40 bar, T: 80° C., t: 18 h.

Yields:

Yield Ligand Halogen [%]

I/Cl 99/0

I/Cl 99/0

I/Cl   99/<1

I/Cl 95/0

Variation of the Equivalents and of the Halogen

Reaction conditions:

1.0 mmol of 1-octene, 1.0 mol % of Pt(acac)₂, LiX (X=halogen), 2.2equivalents of Xantphos (1), solvent: toluene, p(CO/H₂): 40 bar, T: 120°C., t: 20 h.

Equivalents of LiX X Yield [%] 0.5 I 99 1.0 I 99 2.0 I 99 4.0 I 99 4.0CI 0

As the experimental results show, the object is achieved by the processaccording to the invention.

The invention claimed is:
 1. A process comprising the process steps of:a) initially charging an olefin; b) adding a compound of formula (I):

where R¹, R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸ are selected from: —H,—(C₁-C₁₂)-alkyl or —(C₆-C₂₀)—aryl; and, if R¹, R², R³, R⁴, R⁵, R⁶, R⁷and R⁸ are —(C₆-C₂₀)-aryl, the aryl ring may have substituents selectedfrom: —(C₁-C₁₂)-alkyl or —O—(C₁-C₁₂)-alkyl; c) adding a Pt compoundcapable of forming a complex; d) adding an iodine compound; e) feedingin CO and H₂; f) heating the reaction mixture from steps a) to e), toconvert the olefin to an aldehyde.
 2. The process according to claim 1,where R², R³, R⁵, R⁶, R⁷ and R⁸ are selected from: —(C₁-C₁₂)-alkyl or—(C₆-C₂₀)-aryl.
 3. The process according to claim 1, where R⁵, R⁶, R⁷and R⁸ are —(C₆-C₂₀)-aryl.
 4. The process according to claim 1, where R²and R³ are —(C₁-C₁₂)—alkyl.
 5. The process according to claim 1, whereR¹ and R⁴ are —H.
 6. The process according to claim 1, wherein thecompound (I) has the structure (1):


7. The process according to claim 1, wherein the Pt compound is selectedfrom: Pt(II)I₂, Pt(IV)I₄, diphenyl(1,5-COD)Pt(II), Pt(II)(acac)₂,Pt(0)(PPh₃)₄, Pt(0)(DVTS) solution (CAS: 68478-92-2),Pt(0)(ethylene)(PPh3)2, tris(benzylideneacetone)Pt(0), Pt(II)(OAC)₂solution, Pt(0)(t-Bu)₂, Pt(II)(COD)Me₂, Pt(II)(COD)I₂, Pt(IV)IMe₃ orPt(II)(hexafluoroacetylacetonate)₂.
 8. The process according to claim 1,wherein the Pt compound is selected from: Pt(II)I₂ or Pt(II)(acac)₂. 9.The process according to claim 1, wherein the iodine compound isselected from: Pt(II)I₂ or LiI.
 10. The process according to claim 1,wherein the iodine compound is added in an amount in the range of 0.1 to10, measured in equivalents based on Pt.
 11. The process according toclaim 1, comprising the additional process step e′): e′) adding asolvent.
 12. The process according to claim 11, wherein the solvent isselected from: THF, DCM, ACN, heptane, DMF, toluene, texanol, pentane,hexane, octane, isooctane, decane, dodecane, cyclohexane, benzene,xylene, Marlotherm, propylene carbonate, MTBE, diglyme, triglyme,diethyl ether, dioxane, isopropanol, tert-butanol, isononanol,isobutanol, isopentanol or ethyl acetate.
 13. The process according toclaim 1, wherein CO and H₂ are fed in at a pressure in a range from 1MPa (10 bar) to 6 MPa (60 bar).
 14. The process according to claim 1,wherein the reaction mixture is heated to a temperature in the rangefrom 25° C. to 150° C.
 15. The process according to claim 1, wherein theolefin is selected from: ethene, propene, 1-butene, cis- and/ortrans-2-butene, isobutene, 1,3-butadiene, 1-pentene, cis- and/ortrans-2-pentene, 2-methyl-1-butene, 3-methyl-1-butene,2-methyl-2-butene, hexene, tetramethylethylene, heptene, 1-octene,2-octene, di-n -butene or mixtures thereof.